SO, I would like to know what are the models
used in LES to assess the subgrid scale diffusivity of a scalar transported. When I look at the cooles
solver or Xooles sover, I can see that "alphaeFF" is used the h eq. However I couldn't find out
how "alphaEff" is computed.

Is it simply computed from the Prdtl number and thesubgris scale viscosity (as it is apparently in turbulence RANS foam solvers)
OR
is there any computation of alphaEff in a way similar to the dynamic model (by subsituying the velocity field by the h field?

Thanks you to answer me on this point,

Anne

mattijs

July 4, 2006 12:36

You can find the source code i

You can find the source code in $FOAM_SRC/LESmodels/compressible/.

grep -i lnInclude/*

will show you where to start looking.

anne

July 5, 2006 03:37

Hello Mattijs,
I had looked

Hello Mattijs,

I had looked and again I look at the files in LESmodels/compressibles.

I find well how muSGS and thus muEff is computed.
However my concern is with alphaEff, the eddy conductivity or enthaply diffusivity that I can't find out the way it is computed when using LES.

I tried also to find it in thermoproperties directory but I didn't succeed in finding it.

Where is alphaEff computed ?

Thanks you for help

Anne

tehache

July 14, 2008 03:14

Hello,
same problem here:

Hello,

same problem here:

I would like to to incompressible flow + heat transfer + LES. I found the calculation of alphaEff as alpha + muSgs_ in most of the implementations one can find in LESmodels/compressible. However, there is no implementation for the incompressible variants, and especially also not for the Smagorinsky model, which I would like to use. I could simply add that - but I am wondering if there is a good reason why its not there? Is that calculation of alphaEff not suitable for incompressible cases?

As a turbulence modelling newbie, I would be very grateful for any hint....

Thomas

tehache

July 14, 2008 03:30

Hello,
same problem here:

Hello,

same problem here:

I would like to to incompressible flow + heat transfer + LES. I found the calculation of alphaEff as alpha + muSgs_ in most of the implementations one can find in LESmodels/compressible. However, there is no implementation for the incompressible variants, and especially also not for the Smagorinsky model, which I would like to use. I could simply add that - but I am wondering if there is a good reason why its not there? Is that calculation of alphaEff not suitable for incompressible cases?

As a turbulence modelling newbie, I would be very grateful for any hint....

Thomas

tehache

July 14, 2008 08:52

sorry ... should start thinkin

sorry ... should start thinking BEFORE posting ...

... of course I can just calculate my effective thermal diffusivity from the effective viscosity, using some subgrid Prandtl number, externally in my code...

hkb

September 17, 2008 15:31

Hi
I would also like to incor

Hi
I would also like to incorporate heat transfer into an incompressible LES solver, and would be interested in suggestion/comments from others wha have tried.